ECHO HB no longer reaching top speed.

[syllogist]

Hey, I have an automatic 2005 Echo Hatchback LE. My car used to easily reach its top speed of 180-185 km/h.

At this point I can not in anyway go above 170 km/h. I've tried with both overdrive on or off. The car keeps revving up until it reaches 170 and then it just stays at around 4000 RPM, and no amount of throttling of the gas will help.

I did have an issue with a leak in the fuel gasket of my front manifold a few months ago that was repaired under warranty, and all has been fine up until now.

My car has 64000 km on it. The only aftermarket stuff on it are the alloys.

Any hints or info would be greatly appreciated.